Quote Originally Posted by MacSpadger View Post
Obviously someone sat down at some point and made these sept lists up, as seems to be happening in the recent but burgeoning Irish tartan market today. There must be many other people who have surnames appropriated as septs without knowing why. I was just wondering if anyone had any further insight into the matter.
I'm sorry but I have nothing to add to your query, other than somewhere I once read something that primarily agrees with Jock's suspicions.

I have also heard that (modern) clan societies influence these lists as well....in the case of Clan Donald its through genealogical research (the addition or deletion of sept/clan names). As to the how or when their list was first developed, that I couldn't tell you.